1. Field of the Invention
This invention generally relates to a continuously variable bicycle transmission. More specifically, the present invention relates to a continuously variable bicycle transmission having a frictional roller.
2. Background Information
Bicycles are typically provided with a chain drive that includes a rear drive sprocket mounted to a rear hub that is mounted to a rear portion of a frame of a bicycle. Some bicycles are provided with a rear hub that includes an internal gearing mechanism for shift among a plurality of gears to change an output gear ratio from a drive sprocket. This type of rear hub is often called an internally geared hub. Some internally geared hubs are provided with a continuously variable transmission. One example of an internally geared hub having a continuously variable transmission is disclosed in U.S. Pat. No. 7,762,919. In this internally geared hub of this publication, the continuously variable transmission uses spherical speed adjusters that each has a liftable axis of rotation. The spherical speed adjusters are distributed in a plane about a longitudinal axis of the continuously variable transmission.